Promising Corrosion Inhibitor Research Articles

L-tryptophanium picrate as novel anticorrosion agent for mild steel in 5% HCl: A detailed experimental and in silico investigation

Acidizing in petroleum recovery often leads to severe corrosion of mild steel, necessitating the development of highly effective corrosion inhibitors. In this study, L-tryptophanium picrate ( [Trp][Pic]), an amino acid derivative synthesised by one-step synthesis involving two-component acid–base reaction between L-tryptophan and picric acid, is investigated as a novel corrosion inhibitor for mild steel in 5% HCl. A comprehensive experimental and theoretical approach was employed to evaluate its performance. Weight loss measurements, potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) were used to determine the inhibition efficiency. At 30°C, [Trp][Pic] significantly increased the polarization resistance from 81.08 Ω cm² in the uninhibited solution to 462.15 Ω cm² in the presence of 100 ppm of [Trp][Pic], achieving an inhibition efficiency of 82.46%. PDP results confirmed its mixed-type behavior, reducing both anodic and cathodic reactions. Surface analysis through SEM and AFM demonstrated the formation of a uniform protective film of [Trp][Pic] that shielded the steel surface. X-ray photoelectron spectroscopy (XPS) supported the role of donor-acceptor interactions between heteroatoms and Fe atoms in the chemisorption mechanism. Molecular dynamics (MD) simulations identified key binding sites responsible for the strong adsorption of [Trp][Pic], providing insight into the molecular-level mechanism of inhibition. These findings highlight the potential of [Trp][Pic] as a promising corrosion inhibitor for industrial applications.

Evaluation of 14-(p-tolyl)-14H-dibenzo[a,j]xanthene as a highly efficient organic corrosion inhibitor for mild steel in 1 M HCl: Electrochemical, theoretical, and surface characterization

Corrosion of mild steel, particularly in acidic environments such as hydrochloric acid (HCl), remains a critical issue due to its impact on material durability, economic costs, and safety concerns. This study introduces 14-(p-tolyl)-14H-dibenzo[a,j]xanthene (ZM5), a novel and highly effective organic corrosion inhibitor, to mitigate this challenge. Employing advanced electrochemical techniques: electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP), we evaluated ZM5’s performance in a 1 M HCl solution, revealing an impressive inhibition efficiency of 94.7 %. Surface characterization using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) further confirmed the formation of a robust protective film on the steel surface, shedding light on ZM5’s adsorption mechanisms. Complementing the experimental findings, Density Functional Theory (DFT) simulations provided theoretical insights into the anti-corrosion mechanism of ZM5, aligning well with observed results. These findings underscore ZM5's potential as a highly promising corrosion inhibitor for industrial applications, effectively enhancing the corrosion resistance of mild steel in aggressive environments.

Comparative Analysis of Linear Regression, Decision Tree, and Gradient Boosting Models for Predicting Drug Corrosion Inhibition Efficiency Using QSAR Descriptors

<table width="593" border="1" cellspacing="0" cellpadding="0"><tbody><tr><td valign="top" width="388"><p>Corrosion in industrial environments poses significant economic and safety challenges, necessitating the development of effective inhibitors. Organic compounds, particularly pharmaceuticals, have emerged as promising corrosion inhibitors due to their efficiency and environmental benefits. However, predicting these compounds' corrosion inhibition efficiency (CIE) remains complex and requires advanced computational methods. This study investigates the predictive capabilities of three machine learning (ML) models, namely linear regression, decision tree, and gradient boosting regression, using Quantitative Structure-Activity Relationship (QSAR) descriptors. A dataset containing 14 QSAR descriptors was compiled from experimental studies on various pharmaceutical-based inhibitors. The dataset was divided into training (90%) and testing (10%) subsets to evaluate model performance. The research follows the CRISP-DM methodology, a systematic framework that includes data preparation, model training, and evaluation. Key performance metrics, including Mean Squared Error (MSE), Mean Absolute Error (MAE), Root Mean Squared Error (RMSE), and the coefficient of determination (R²), were used to assess model accuracy. Among the models, Gradient Boosting Regression achieved the most promising results, with the lowest MSE (21.52) and the highest R² (0.21), reflecting its ability to capture non-linear relationships in the data. Despite the relatively modest R², this model demonstrates the potential for improving computational approaches to corrosion inhibition prediction. This study highlights the value of machine learning in optimizing the selection of corrosion inhibitors, potentially reducing the reliance on extensive laboratory testing and accelerating the discovery of efficient, eco-friendly solutions for industrial applications.</p></td></tr></tbody></table>

Theoretical study of novel antipyrine derivatives as promising corrosion inhibitors for mild steel in an acidic environment

Theoretical study of novel antipyrine derivatives as promising corrosion inhibitors for mild steel in an acidic environment

Chitosan grafted with gallic acid and cerium dioxide hybrid nanocomposites as environmentally friendly corrosion inhibitors for mild steel: An experimental and computational study

Chitosan grafted with gallic acid (CS-GA), along with CS-GA doped with CeO2 nanoparticles (CS-GA-CeO2) were synthesized as novel environmentally friendly mild steel corrosion inhibitors. The formation of these derivatives was confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), hydrogen nuclear magnetic resonance spectroscopy (1H NMR), and thermal analysis (TGA). Based on potentiodynamic polarization curves (PDP) measurements, the inhibitors acted primarily as hybrid inhibitors, while following the Langmuir adsorption theory model. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy(XPS) and 3D surface profiles, confirmed that CS-GA-CeO2 adsorbed on the mild steel forming a protective layer thus preventing the invasion of corrosive media. The corrosion protection mechanism of chitosan derivatives was investigated by molecular dynamics simulations. Electrochemical measurements were used to investigate the corrosion inhibition by CS-GA and CS-GA-CeO2 on mild steel in a 3.5 % NaCl solution. At room temperature, the highest inhibition efficiency (93.58 %) was achieved at 200 ppm CS-GA-CeO2. Modified chitosan nanocomposites were confirmed as promising corrosion inhibitors.

Lawsonia inermis as an Active Corrosion Inhibitor for Mild Steel in Hydrochloric Acid

Corrosion is a pervasive issue affecting metallic materials, with significant economic losses and safety risks in various industries. Mild steel, extensively used in construction and infrastructure, faces corrosion challenges, needing continuous research to effectively tackle them. Natural compounds, because of their eco-friendliness and corrosion inhibition potential, are attracting increasing interest for corrosion control. Lawsonia inermis (LI), or henna, a plant native to North Africa and South Asia, has bioactive compounds exhibiting corrosion inhibitive properties. This study comprehensively explores Lawsonia inermis’s effectiveness as a corrosion inhibitor for mild steel, filling a gap in the existing research. Various concentrations of Lawsonia inermis extract were tested in acidic solutions to evaluate corrosion inhibition. Experimental results indicate a significant reduction in the corrosion rate with increasing inhibitor concentration. Langmuir adsorption isothermal analyses reveal the adsorption mechanism as being an interplay between physisorption and weak chemisorption. Electrochemical measurements demonstrate Lawsonia inermis’s capability to alter both cathodic and anodic reactions, leading to improved corrosion resistance. Scanning electron microscopy reveals a more even surface morphology in the presence of the Lawsonia inermis, indicating corrosion inhibition. Gas chromatography–mass spectrometry (GC-MS) analyses identified organic compounds in Lawsonia inermis extract responsible for corrosion inhibition. Overall, Lawsonia inermis emerges as a promising corrosion inhibitor for mild steel, offering excellent inhibition efficiencies. This study sheds light on its adsorption behaviour and provides insights into its mechanism of action. These findings underscore Lawsonia inermis’s potential as a green corrosion inhibitor, paving the way for its practical application in industrial corrosion protection strategies.

New type of tri‐pyridyl inhibitor‐loaded polyaniline nanospheres for durable protection anticorrosion coatings

AbstractPolyaniline (PANI) is considered as one of the most promising corrosion inhibitors because of its unique redox and environmental stability. Pyridine and its derivatives can chelate metal ions during corrosion, forming an inert protective layer on the metal surface to achieve the anticorrosion effect. Therefore, polyaniline is combined with pyridine together to achieve deep anticorrosion in this work. 4‐((2,2′:6′,2″‐terpyridin)‐4′‐yl)aniline (TPY) and 1,3,5‐benzenetricarbonyl chloride (TMC) were applied to synthesize a novel corrosion inhibitor N1, N3, N5‐tri (4‐((2,2′: 6′, 2′‐tri‐pyridine)‐4′‐yl) phenyl) benzene‐1,3,5‐tri‐formamide (TBT). Then, TBT was in situ loaded onto the PANI surface to obtain the composite TPANI. The TPANI was successfully dispersed in epoxy resin (EP) at various dosages to prepare composite coatings. Electrochemical impedance spectroscopy and salt fog tests were employed to evaluate the performance of the coatings. After experimentation, we discovered that when the TPANI content was 0.25 wt%, the impedance value remained stable at 5.83 × 109 Ω cm2 after immersing the coatings in a 3.5 wt% NaCl solution for 28 days. In contrast, the EP coating exhibited a resistance decrease ranging from 9.56 × 109 to 7.8 × 108 Ω cm2 within the same soaking time, decreasing by an order of magnitude, while the TPANI‐0.25% coating still maintaining a high order of magnitude. These results indicated that the TPANI filler effectively preserved long‐term stability and provided persistent protection against corrosion. The protective mechanism of TPANI composite coatings was further elucidated through detailed analysis. Overall, the incorporation of TPANI into the epoxy resin yielded promising results, demonstrating its potential as an effective corrosion inhibitor for protective coatings.

Implementation of Polynomial Functions to Improve the Accuracy of Machine Learning Models in Predicting the Corrosion Inhibition Efficiency of Pyridine-Quinoline Compounds as Corrosion Inhibitors

Historically, the exploration of corrosion inhibitor technology has relied extensively on experimental methodologies, which are inherently associated with substantial costs, prolonged durations, and significant resource utilization. However, the emergence of ML approaches has recently garnered attention as a promising avenue for investigating potential materials with corrosion inhibition properties. This study endeavors to enhance the predictive capacity of ML models by leveraging polynomial functions. Specifically, the investigation focuses on assessing the effectiveness of pyridinequinoline compounds in mitigating corrosion. Diverse ML models were systematically evaluated, integrating polynomial functions to augment their predictive capabilities. The integration of polynomial functions notably amplifies the predictive accuracy across all tested models. Notably, the SVR model emerges as the most adept, exhibiting R² of 0.936 and RMSE of 0.093. The outcomes of this inquiry underscore a significant enhancement in predictive accuracy facilitated by the incorporation of polynomial functions within ML models. The proposed SVR model stands out as a robust tool for prognosticating the corrosion inhibition potential of pyridine-quinoline compounds. This pioneering approach contributes invaluable insights into advancing machine learning methodologies geared toward designing and engineering materials with promising corrosion inhibition properties.
 Keywords: machine learning, polynomial, corrosion inhibition, pyridine-quinoline

Mechanistic insights into the corrosion inhibition of mild steel by eco-benign Asphodelus Tenuifolius aerial extract in acidic environment: Electrochemical and computational analysis

This study explores the novel application of Asphodelus Tenuifolius aerial extract (ATAE) as a corrosion inhibitor for mild steel in a 0.5 M HCl acidic environment. By utilizing techniques such as electrochemical measurements, gravimetric analysis, SEM, and CA assessments, the inhibitory potential of ATAE has been comprehensively evaluated. The results revealed a concentration-dependent enhancement in corrosion resistance, classifying ATAE as a mixed-type inhibitor by measuring the anodic (βa) and cathodic (βc) polarization slope values of 108.89 and −129.33 mV/dec. The peak inhibition efficiency was observed at 250 ppm, reaching an impressive IE% of 94.40 % at 298 K (Kelvin). The electrochemical analysis demonstrated a significant increase in charge transfer resistance (Rct) and polarization resistance (Rp) values, coupled with a decrease in Constant Phase Element (CPE.Yo) value to 162.94 μF, indicating heightened corrosion inhibition potential. Additionally, Theoretical calculations emphasized a strong interaction between ATAE and mild steel surface, characterized by a low energy gap (ΔE), indicating excellent anti-corrosion abilities at the micro-level. This study positions ATAE as a promising corrosion inhibitor, offering insights for further research in corrosion prevention strategies using a sustainable corrosion inhibitor.

(Invited) On the Inhibition Mechanism of an Alkylammonium Nitrate Ionic Liquid Family on Al Alloys: Electrochemical and XPS/in Situ PM-IRRAS Studies

AA2024 are high strength Al alloys widely used in the aerospace industry due to their excellent strength to weight ratio. However, their high susceptibility to localised corrosion, caused by the presence of intermetallic particles embedded in the Al matrix, requires the use of chromate-based surface treatment formulations1. Several alternatives have been explored in the last decades, such as vanadates, chromium (III) based conversion coatings, rare-earth inhibitors or more recently, lithium containing conversion coatings2. However, these alternatives are often not versatile (cannot be transposed to all alloy systems) or are not as cost effective as chromates. Ionic liquids (ILs), usually defined as salts with a melting point below 100°C, can be considered as promising corrosion inhibitors due to their low vapour pressure, chemical and thermal stability3. In addition, they can exhibit versatile inhibition properties associated with the quasi-infinite possible anion-cation combinations3–5. In previous work, the effect of an alkylammonium nitrate IL family, namely ethylammonium nitrate (EAN), propylammonium nitrate (PAN), and butylammonium nitrate (BAN) as potential corrosion inhibitors for an AA2024-T6 Al alloy was investigated6. Electrochemical tests such as potentiodynamic polarisation and electrochemical impedance spectroscopy were performed to identify the effect of the anion and cation on the anodic and cathodic kinetics. Herein, surface analysis was performed to rationalise the electrochemical results, particularly on the reactivity of NO3 - and R-NH3 + on the Cu-rich intermetallic particles. To this end, electrospray ionisation of EAN, BAN and NaNO3 was realised on Cu. The effect of the IL concentration and cation chain length, using PM-IRRAS (polarisation modulation -infrared reflection adsorption spectroscopy) was used to investigate molecule orientation and surface-molecule bonding as a function of surface coverage; The results provided new insights on the inhibition mechanism of this IL family. O. Gharbi, S. Thomas, C. Smith, and N. Birbilis, Npj Mater Degrad, 2, 12 (2018) http://www.nature.com/articles/s41529-018-0034-5.A. Kosari et al., Corros Sci, 190, 109651 (2021) https://doi.org/10.1016/j.corsci.2021.109651.C. Verma, E. E. Ebenso, and M. A. Quraishi, J Mol Liq, 233, 403–414 (2017) http://dx.doi.org/10.1016/j.molliq.2017.02.111.J. Sun, P. C. Howlett, D. R. MacFarlane, J. Lin, and M. Forsyth, Electrochim Acta, 54, 254–260 (2008).N. V. Likhanova et al., Corros Sci, 52, 2088–2097 (2010) http://dx.doi.org/10.1016/j.corsci.2010.02.030.A. Z. Benbouzid et al., Corrosion Communications, 9, 57–64 (2023).

Fish processing discards extract as an eco-friendly corrosion inhibitor for carbon steel in hydrochloric acid

The objective of this study is to extract amino acids from fish processing discards for the preparation of highly effective and degradable corrosion inhibitors. The composition of fish processing discards extract (FPDE) was characterized by HPLC and FTIR. The results showed that the main components of FPDE are amino acids and contain a large number of unsaturated functional groups. Electrochemical techniques (electrochemical impedance spectroscopy (EIS) and Tafel), surface analysis (XPS and AFM), and molecular dynamics simulations (MDS) were conducted to investigate the corrosion inhibition mechanism of FPDE for carbon steel in 1 mol/L HCl. As shown by electrochemical tests, FPDE exhibits mixed-type corrosion inhibition with a maximum inhibition efficiency of 93.3%. FPDE exhibits excellent corrosion inhibition properties on carbon steel surfaces by forming a high coverage film through chemisorption and physisorption. Indeed, the advantages of remarkable inhibition efficiency and facile extraction methods allow FPDE to become a promising corrosion inhibitor for practical applications.

The inhibition effect of etidronate on degradation behavior of Mg–Zn–Y-Nd-Zr alloy

The control of corrosion behavior of Mg alloys for biomedical applications is a research hotspot in the field of biodegradable metallic implant materials. In recent years, the employment of corrosion inhibitors for regulating the corrosion behavior of Mg alloys has attracted attention. In this work, a promising corrosion inhibitor for Mg alloys, Etidronate (ETN), was selected from the drugs for the treatment of osteoporosis, and its effect on the corrosion behavior of Mg–Zn–Y-Nd-Zr (ZE21C Mg alloy) in simulated body fluids was systematically studied. The results show that ETN not only reduces the corrosion rate of the alloy, but also significantly weakens its tendency of localized corrosion, which is beneficial for improving the service reliability of Mg alloy for orthopedic application. This study provides an idea for corrosion control of biodegradable Mg alloys and is of great significance for promoting their development and applications.

Thiosemicarbazide and its derivatives as promising corrosion inhibitors: A Mini-Review

Thiosemicarbazide and its derivatives as promising corrosion inhibitors: A Mini-Review

Theoretical and experimental insights into the C-steel aqueous corrosion inhibition at elevated temperatures in 1.0 M HCl via multi-carbonyl Gemini cationic surfactants

Abstract Despite corrosion being an inevitable process, researchers strive to control corrosion. In this study, our goal was to prepare two amido Gemini cationic surfactants, LAPG and MAPG, each with different alkyl chains and multiple carbonyl groups as rich electronic rich centers. We aimed to evaluate these surfactants as potential corrosion inhibitors for carbon steel (CS) in 1 M HCl at temperatures of 25–55 ± 0.1 °C. In theoretical investigations, DFT parameters and Mont Carlo simulation were run to predict the adsorption affinity and reactive sites of the LAPG and MAPG molecules. Their efficacy was investigated experimentally considering weight loss and electrochemical techniques. The Tafel polarization revealed that at 0.1 mM of LAPG and MAPG, the corrosion current density (i corr) of CS was reduced to the lowest extent (75.56 and 53.82 μA cm−2) compared to 529.3 μA cm−2 in the absence of the inhibitors. EIS data suggests the enhancement of the thickness of the adsorbed layers of the studied compounds from the decrease of the double-layer capacitance C dl values. The Langmuir isotherm explained the adoption phenomena of these compounds at 25–55 ± 0.1 °C. Activation and adsorption thermodynamic parameters predicted the chemisorption behavior of these molecules onto the steel surface. AFM and XPS tools confirm the CS surface protection due to these inhibitors’ adsorbed layer. A parallel study showed the superiority of these corrosion inhibitors in HCl compared with those reported earlier, making these compounds highly promising corrosion inhibitors, especially in high-temperature acidic environments.

Experimental and detailed DFT/MD simulation of α-aminophosphonates as promising corrosion inhibitor for XC48 carbon steel in HCl environment

BackgroundCorrosion is a pervasive issue in several industries, causing safety hazards and substantial economic losses. α-aminophosphonate substances have recently garnered attention for their ability to inhibit corrosion. In this study, two specific α-aminophosphonate molecules, namely diethyl(furan-2-yl(phenylamino)methyl) phosphonate (AMP1) and diethyl((2methoxyphenyl) amino) (thiophene-2-methyl) phosphonate (AMP2) were evaluated for their potential as anticorrosion agents for XC48 carbon steel under acidic conditions. MethodsTheir corrosion inhibition was examined towards XC48 carbon steel under 1.0 M HCl solution utilizing the electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), atomic force microscope (AFM), scanning electron microscope (SEM), contact angle, Density functional theory (DFT), molecular dynamics (MD), and atoms in molecule (AIM). Significant findingsResults showed that AMP1 and AMP2 had inhibition efficiencies of 83.34% and 63.82% for EIS and 82.70% and 74.57% for PDP, respectively. The inhibition mechanism involved adsorption of the additives onto the metal surface via Langmuir isotherm. The study also demonstrated the influence of temperature on inhibition efficiency, with nearly 70% inhibition observed at 298 to 323 K. AFM and SEM analyses revealed chemisorption coating formation inhibiting acid attack, and contact angle analyses showed the surface to be hydrophobic. Theoretical analyses using DFT, MD, and AIM were used to clarify the inhibitors' adsorption effect on XC48 steel, showing a high agreement with experimental findings.

Experimental and Computational Studies of Two Cu (II) and Zn (II) Coordination Polymers Based on Acyclic Cryptate-Bis(1H-1,2,4-Triazole) as Promising Corrosion Inhibitors in Molar HCl Medium

Experimental and Computational Studies of Two Cu (II) and Zn (II) Coordination Polymers Based on Acyclic Cryptate-Bis(1H-1,2,4-Triazole) as Promising Corrosion Inhibitors in Molar HCl Medium

Revealing the Correlation between Molecular Structure and Corrosion Inhibition Characteristics of N-Heterocycles in Terms of Substituent Groups

Controlling metal corrosion can directly address the waste of metal and the environmental pollution and resource depletion caused by metal recycling, very significant factors for green and sustainable development. The addition of corrosion inhibitors is a relatively cost-effective means of corrosion prevention. Among these, N-heterocycles have been widely used because heteroatoms contain lone pairs of electrons that can be strongly adsorbed onto metals, protecting them in highly corrosive environments at relatively low concentrations. However, due to the large variety of N-heterocycles, their corrosion inhibition characteristics have seldom been compared; therefore, the selection of appropriate N-heterocycles in the development of anti-corrosion products for specific applications was very difficult. This review systematically analyzed the influence of different substituents on the corrosion inhibition performance of N-heterocycles, including different alkyl chain substituents, electron-donating and electron-withdrawing substituents, and halogen atoms, respectively. The correlation between the molecular structure and corrosion inhibition characteristics of N-heterocycles was comprehensively revealed, and their action mechanism was analyzed deeply. In addition, the toxicity and biodegradability of N-heterocycles was briefly discussed. This study has provided a significant guideline for the development of green, promising corrosion inhibitors for advanced manufacturing and clean energy equipment protection.

Electrochemical, surface analysis, and theoretical investigation of 3-hydroxy-5-(phenylamino)-4-(p-tolyldiazenyl)thiophen-2-yl)(phenyl)methanone as a corrosion inhibitor for carbon steel in a molar hydrochloric acid solution

In this work, a comprehensive study for using (3-hydroxy-5-(phenylamino)-4-(p-tolyldiazenyl)thiophen-2-yl)(phenyl)methanone as a corrosion inhibitor for carbon steel in a 1.0 M HCl was performed. For this purpose, different types of electrochemical and surface analysis techniques as well as a computational simulations have been applied. The obtained experimental results showed that the investigated compound is a promising corrosion inhibitor for carbon steel in acidic environments. Adding a low inhibitor concentration of about 5 × 10−5 M at room temperature resulted in an inhibition efficiency of up to 93.25 %. The inhibition efficiency increases with increasing inhibitor concentration while decreasing with increasing temperature. This trend has been demonstrated and discussed precisely by potentiodynamic polarization (PDP) measurements. SEM and AFM were used to examine the surface morphology of the electrode before and after inhibition. The inhibitor adsorbs on the surface of the steel, acting as a barrier at the steel/HCl acid interface and thus blocking the steel electrode's surface. DFT calculations and MC simulations were used to demonstrate the adsorption process. The findings also revealed that it is a mixed-type inhibitor that follows Henry's adsorption isotherm. The experimental and theoretical studies agree remarkably well. The inhibition mechanism has also been discussed.

The use of methanol extract of Rheum Ribes (Işgın) flower as a natural and promising corrosion inhibitor for mild steel protection in 1 M HCl solution

There is a tendency towards natural products with the increase in sensitivity to the environment, people and other living things around the world. In recent years, there has been a similar trend regarding inhibitors used in the metals protection against corrosion. In this study, the adsorption and protection ability of Rheum ribes (RR) flower extract on mild steel (MS) corrosion in 1 M HCl solution were investigated with the help of many electrochemical techniques. The MS surface after exposing to the test solutions was examined by energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and contact angle measurements. Some thermodynamic parameters corresponding to the adsorption of extract molecules on the MS surface and excess surface charge of the steel in the extract containing solution were calculated and a possible mechanism of the corrosion inhibition process was discussed. The durability of the extract film formed on the MS surface was examined under potentiodynamic and potentiostatic conditions. It was found that an adherent and uniformly distributed extract film formed on the MS surface, which is responsible for the inhibition of corrosion. The flower extract provided 94.7 % and 98.4 % protection efficiencies at 1000 ppm concentration after 1 h and 6 h exposure. RR flower extract mitigated both anodic and cathodic reactions, predominantly cathodic process. The extract molecules interact and bond to the MS surface via physical and chemical interactions. The extract could be suggested as a promising natural corrosion inhibitor for MS protection in 1 M HCl solution.

Evaluation of synthesized biosurfactants as promising corrosion inhibitors and alternative antibacterial and antidermatophytes agents

This study investigated different amino acid-based surfactants (AASs), also known as biosurfactants, including sodium N-dodecyl asparagine (AS), sodium N-dodecyl tryptophan (TS), and sodium N-dodecyl histidine (HS) for their potential anticorrosion, antibacterial, and antidermatophyte properties. The chemical and electrochemical techniques were employed to examine the copper corrosion inhibition efficacy in H2SO4 (1.0 M) solution at 298 K. The results indicated their promising corrosion inhibition efficiencies (% IEs), which varied with the biosurfactant structures and concentrations, and the concentrations of corrosive medium. Higher % IEs values were attributed to the surfactant adsorption on the copper surface and the production of a protective film. The adsorption was in agreement with Langmuir adsorption isotherm. The kinetics and mechanisms of copper corrosion and its inhibition by the examined AASs were illuminated. The surfactants behaved as mixed-kind inhibitors with minor anodic priority. The values of % IEs gained from weight loss technique at a 500 ppm of the tested surfactants were set to be 81, 83 and 88 for AS, HS and TS, respectively. The values of % IEs acquired from all the applied techniques were almost consistent which were increased in the order: TS > HS ≥ AS, establishing the validity of this study. These surfactants also exhibited strong broad-spectrum activities against pathogenic Gram-negative and Gram-positive bacteria and dermatophytes. HS exhibited the highest antimicrobial activity followed by TS, and AS. The sensitivity of pathogenic bacteria varied against tested AASs. Shigella dysenteriae and Trichophyton mantigrophytes were found to be the most sensitive pathogens. HS exhibited the highest antibacterial activity against Shigella dysenteriae, Bacillus cereus, E. coli, K. pneumoniae, and S. aureus through the formation of clear zones of 70, 50, 40, 39, and 35 mm diameters, respectively.AASs also exhibited strong antifungal activity against all the tested dermatophyte molds and fungi. HS caused the inhibition zones of 62, 57, 56, 48, and 36 mm diameters against Trichophyton mantigrophytes, Trichophyton rubrum, Candida albicans, Trichosporon cataneum, and Cryptococcus neoformans, respectively. AASs minimal lethal concentrations ranged between 16 to 128 µg/ml. HS presented the lowest value (16 µg/ml) against tested pathogens followed by TS (64 µg/ml), and AS (128 µg/ml). Therefore, AASs, especially HS, could serve as an effective alternative antimicrobial agent against food-borne pathogenic bacteria and skin infections-associated dermatophyte fungi.